Method for the production of structural components from fiber-reinforced thermoplastic material

ABSTRACT

The method enables the series production of light structural components out of long-fiber thermoplastic material (LFT) with integrated continuous fiber (CF)-reinforcements in a single stage LFT-pressing step. In this, CF-tapes ( 5 ) are melted open and transferred into a profile tool ( 21 ) of a CF-profile forming station ( 20 ), there are pressed for a short time period and shaped into the required CF-profile ( 10 ). In doing so, by means of contact with the thermally conditioned profile tool ( 21 ) on the profile surface ( 11 ) a shock-cooled, dimensionally stable, thin casing layer ( 12 ) is formed and the inside of the CF-profile remains melted. Following a defined short shock-cooling period (ts), the CF-profile ( 10 ) is transferred into an LFT-tool ( 31 ) and pressed together with an introduced molten LFT-mass ( 6 ). In doing so, the casing layer ( 12 ) is melted open again on the surface ( 11 ) and is thermoplastically bonded together with the surrounding LFT-mass.

BACKGROUND

The invention is related to a method for the production of structuralcomponents from long fiber thermoplastic with integrated continuousfiber reinforcements as well as to an installation for the production ofstructural components of this kind. Known methods for the production ofsuch structural components in most cases utilise plane continuous fiberreinforcements, e.g., in the form of semi-finished fabric products orwith a sandwich structure, which, however, are very limited with respectto possible shaping and applications.

From international patent application publication WO99/52703 a methodfor the production of structural components is known, in the case ofwhich molten continuous fiber strands are deposited on top of oneanother, so that they form a coherent load-bearing structure with planejoints and are pressed in a tool together with a forming mass reinforcedwith long fibers. Also these known processes, however, still manifestessential disadvantages with respect to efficient production,reproducibility and a defined development of an integrated continuousfiber load-bearing structure. In this manner it is not possible toproduce a defined, single piece structural component, which can be madein a single press step and which comprises an integrated, preciselydefined, optimally positioned and shaped, load-optimised continuousfiber reinforcing structure.

It would therefore be very desirable to overcome the disadvantages andlimitations of the known production methods and to create a method forthe efficient automatic production of structural components, whichovercomes the disadvantages and limitations applicable up until now andto produce single piece components capable of being pressed in a singlestep and with an integrated, precisely defined, optimally positioned andthree-dimensionally shaped reinforcing structure, which corresponds tothe loads and forces to be absorbed.

SUMMARY OF THE INVENTION

According to the invention, a method for the production of structuralcomponents is disclosed, and by an installation for the production ofstructural components. By means of the defined, short shock-cooling withCF (continuous fiber)-profile shaping and the formation of adimensionally stable casing layer a precisely defined shape andpositioning of CF-profiles in the LFT (long fiber thermoplastic)—mass aswell as an optimum bonding at the interface is achieved.

Also disclosed are advantageous further developments of the inventionwith particular advantages with respect to efficient cost-effectiveseries production capable of being automated, with short cycle times aswell as optimum alignment and forming of the continuous fiberreinforcing structures with improved mechanical characteristics. Withthis, it is possible to produce light structural components for a largenumber of applications, e.g., for means of transportation, vehicles andvehicle components with load-bearing functions and this in a simple andprecise manner.

DESCRIPTION OF THE DRAWING

The invention will be described with respect to a drawing in severalfigures. What is shown is:

FIG. 1—schematically the method according to the invention with profileshaping and defined shock-cooling,

FIG. 2—temperature dependence in a CF—profile during the shock-coolingfor different shock-cooling periods,

FIG. 3—temperature dependence in a CF—profile during the shock-coolingfor different tool temperatures and heat transfers,

FIG. 4—an example with the shock-cooling differing zone by zone on aCF—profile,

FIG. 5 a—the enthalpy as a function of the temperature during theheating-up and cooling-down of partially crystalline thermoplastics witha crystallisation hysteresis range,

FIG. 5 b—the temperature control on the surface during the shock-coolingin the enthalpy diagram,

FIG. 5 c—the temperature control in the lower layer during theshock-cooling in the enthalpy diagram,

FIG. 6—the temperature distribution in the CF—profile following theshock-cooling,

FIG. 7—the temperature distribution in the CF—profile and in theLFT—layer during the pressing in the LFT—tool,

FIG. 8 a—an arrangement of several CF-profiles in a structural componentwith a three-dimensional intersection point,

FIG. 8 b—the LFT—shaping of the structural component with integratedCF-profiles,

FIG. 8 c—a two-stage profile forming process,

FIG. 9 a, b—two different cross section shapes of a CF-profile atdifferent places in a rib,

FIG. 10—an inverse tempered CF-profile,

FIG. 11—a CF-profile production line with a CF-profile—forming station,

FIG. 12—an installation for the production of the structural componentsaccording to the invention with CF-profile forming station andLFT-press,

FIG. 13—a positioning of CF-profiles on top and at the bottom in anLFT-pressing tool,

FIG. 14—a structural component as a bumper beam support, and

FIG. 15—a structural component as an assembly support (front end).

Where possible, like items among the various figures have been indicatedwith like reference designations.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates the method according to the inventionfor the production of structural components out of long-fiberthermoplastic material (LFT) with integrated continuous fiber(CF)-reinforcements in a single stage LFT-pressing process by means ofshock-cooling and CF-profile compression moulding in its sequence.

In a heating station 15 impregnated, particularly, pre-consolidatedCF-tapes or bands 5 are completely melted to a practically homogeneoustemperature Tp0, which is selected to be well above the melting pointTm, and subsequently transferred into a two-part profile tool 21 (herein 21 u where “u” means “under”) of a CF-profile forming station 20.Here the CF-tapes 5 with an input temperature Tp are formed into achosen CF-profile 10 by means of pressing for a short time during aprecisely defined shock-cooling period ts. During this form pressing andshock-cooling, a shock-cooled, dimensionally stable thin casing layer 12is formed through the contact of the CF material with the thermallyconditioned profile tool 21, namely, 210 (“over”) and 21 u (“under”),with a defined, relatively low tool temperature Twp and through a highheat transfer Q1 from the hot CF-profile into the profile tool 21. Aswill be discussed in more detail below, the tool 21 has an ability toconduct a lot of heat away from the CF material very quickly, and thisis advantageous for later method steps.

After a defined shock-cooling—and pressing period ts, the CF-profile 10is immediately completely separated from the profile tool, transferredinto an LFT-tool 31 (310 meaning “over”, 31 u meaning “under”) of anLFT-press 30 and there positioned in a precisely defined manner insuitable shapings of the tool. Subsequently a molten LFT-mass 6 with atemperature Tf, which is situated above the melting point Tm, isintroduced and put under pressure together with the CF-profile 10 andpressed, so that the casing layer 12 at the surface 11 of theCF-profiles is melted open again and is thermoplastically meltedtogether with the introduced surrounding LFT-mass 6. In this way thenewly introduced LFT material is able to form a very good bond with theouter layer of the CF material.

The structural components being combined in the previously mentionedstep include at least one integrated, shock-cooled CF-profile. Thetemperature control during this process, i.e., the adjustment of thethermal and temporal parameters and of the shock-cooling period ts takesplace in correspondence with requirements which will presently bediscussed, which are capable of being achieved with the method accordingto the invention:

a—At the contact points of the CF-profile with a gripper for thetransfer into the LFT-press 30, a non-sticking, solid profile surface isformed.

b—The dimensional stability of the CF-profiles 10 during the transferinto the LFT-press has to be sufficient, so that the CF-profiles arecapable of being positioned in the LFT-tool precisely in the requiredposition and shape.

c—The shape preservation of the CF-profile during the pressing with theLFT-mass 6 in the LFT-press is adjusted in such a manner, that followingthe pressing the required final shape of the CF-profile results in thecomponent doing what is needed in each particular location. For examplein some particular locations it will be desired that the CF-profilepreserves its shape completely, while in other particular locations itwill be desired that the CF-profile merges fully into the surroundingLFT-mass.

d—The interface joint at the contact surfaces 9 between the CF-profileand the surrounding LFT-mass has to achieve the required strength.

As will be discussed below, the method can be carried out so as todevelop a thinner or thicker solidified casing layer 12.

Experience shows that as a general matter, the greater theshock-cooling, the greater the preservation of the shape(characteristics a, b, c) while with a lesser shock-cooling the shapechange during the pressing is enhanced and the interface bonding(characteristic d) is strengthened at the beginning.

An example with a high degree of shape preservation is shown in FIG. 9 awith a CF-profile in a rib. On one side of the CF-profile (adjacent tothe lower LFT-tool 31 u) a stronger shock-cooling with a stronger casinglayer is able to take place, while on the opposite side of theCF-profile nonetheless a good interface bonding with the introducedsurrounding LFT-mass 6 is achieved by means of a medium shock-coolingwith a normally formed casing layer (on the side of the upper LFT-tool310 of FIG. 1).

In general a surface 11 of the CF-profiles adjacent to the LFT-tool 31is able to be previously strongly shock-cooled on one side (because itwill not later be required to be bonded to the LFT-mass) andsimultaneously the opposite side is able to be shock-cooled lessstrongly for the optimum bonding with the LFT-mass (refer to FIG. 4).

The optimum temperature control corresponding to the respectiverequirements of the CF-profiles (10) is achieved by a correspondingadjustment of the process parameters. These are:

Tp—the input temperature of the CF-profile prior to the shock-cooling,after the heating up to a homogeneous temperature Tp0 in the heatingstation 15.

During the shock-cooling:

ts—the shock-cooling period, i.e., the duration of the pressing and withthis of the heat transfer Q1

Twp—the temperature of the profile tool 21

ae—the heat penetration coefficient during the contact with the tool 21;this is determined by the choice of material and the characteristics ofthe tool: specific heat c, thermal conductivity λ and specific densityp. This results in ae=(λ·p·C)^(1/2).

Q1—the heat transfer from the CF-profile 10 to the tool 21 is thereforegiven by Q1=f(ts, Tp−Twp, ae).

Ta, Ti—temperatures on the surface 11 of the surface or inside of theCF-profile

tt—transfer time up to the contact of the CF-profile with the LFT-massin the LFT-press.

Heat transfer during the LFT-pressing:

Tf—temperature of the introduced LFT-mass 6 prior to the pressing

Twl—temperature of the LFT-tool 31

Q2—the heat transfer from the hot LFT-mass 6 to the CF-profile 10 hereresults as a function f(Q1, Ta, Ti, Tf, Twl).

During the adjustment of these parameters, also the thickness dp of theCF-profiles and the materials characteristics are included. Thethickness dp, for example, may be between 2 and 5 mm.

FIGS. 2, 3, 6, and 7 each portray a physical distribution oftemperatures. In each figure, one or more graphed lines will each depicttemperature as a function of position for a particular time. Forexample, in FIG. 2, there is a mass of material 10 between two toolsurfaces 11. The two surfaces to the left and right of FIG. 2 may, forexample, be the surfaces 11 at the top and bottom of the center region20 in FIG. 1. In FIG. 2, a top curve containing point Tp represents atemperature distribution as a function of position when the material 10has first been introduced and before very much heat has been conductedaway from the material 10. In FIG. 2, the next curve downwards containsa point Ti2 and portrays a temperature distribution as a function ofposition after an amount of heat Q1.2 has been extracted from the massof material 10. In this same figure, the next curve downwards contains apoint Ti1 and portrays a temperature distribution as a function ofposition after an amount of heat Q1.1 has been extracted from the massof material 10.

FIGS. 2, 3 schematically illustrate different settings of theshock-cooling parameters. They illustrate temperature dependences in aCF-profile T(d) over the layer thickness dp after a shock-coolingcarried out at the time t=ts.

FIG. 2 illustrates two temperature dependences T1(d), T2(d) for twodifferent shock-cooling periods ts1, ts2, with the same tool temperatureTwp. The longer shock-cooling period ts1 with a heat transfer Q1.1results in a correspondingly stronger, thicker casing layer 12.1(solidified below the melting temperature Tm) and the shortershock-cooling period ts2 with a lesser heat transfer Q1.2 results in athinner casing layer 12.2.

FIG. 3 illustrates different temperature dependences T(d) with aconstant shock-cooling period ts, however, with different tooltemperatures Twp1, Twp2, Twp3 with corresponding heat transfers Q andthe resulting casing layers 12, wherein the intensity of theshock-cooling decreases from T1 to T4 (refer to FIG. 4):

T1: Twp1=strong shock-cooling Q1.1 and casing layer 12.1

T2: Twp2=medium shock-cooling Q1.2 and casing layer 12.2

T3: Twp3=weak shock-cooling Q1.3 and casing layer 12.3

T4: no contact with the tool (open points, recesses, FIG. 4), Q1.4=0,i.e., no thermal transfer.

In this, the surface temperatures Ta of the CF-profile correspond to thetool temperatures Twp and the temperatures inside the profile Ti aresituated in the vicinity of the input temperature Tp of the heatedCF-tape. It is thought preferable to use short shock-cooling periods tsand low tool temperatures.

The shock-cooling periods ts are preferably between 1 and 5 sec., andare more preferably approximately 2-4 sec., although in special casesalso longer times, e.g., of up to 10 sec. would be possible. Thetransfer times tt in the LFT-press amount to, e.g., between 5 and 20sec.

By means of the adjustment of the parameters, and by controllingtemperatures, the shock-cooling is correspondingly adjusted to therespective requirements in order to:

achieve the optimum dimensional stability for the handling of theCF-profiles and for the required final shape of the profile after thepressing operation and

achieve an optimum bonding between the CF-profile and the LFT-mass (bondstrength).

Differing requirements in certain zones, however, may be demanded of aCF-profile (with respect to the criteria a, b, c, d mentioned above),for example because of the intended function of the respective part orof the side or of the zone of a CF-profile. For example, with aCF-profile of FIG. 9 a or in the case of a component of FIG. 8, it isnecessary to take into account the intended zones of force transfers andforce introductions.

It is a very important advantage of the shock-cooling and profileshaping according to the invention, that the shock-cooling on theEP-profiles is capable of being adjusted on a zone-by-zone basisdifferently and respectively for each zone. FIG. 4 shows how this may beadjusted on a zone-by-zone basis. FIG. 4 schematically illustratesdifferent zones with differing shock-cooling in each of the zones, withthe zones distributed longitudinally on a CF-profile 10. In thisexample, each of zones Q1.1 to Q1.4 has its own amount of shock-cooling,in analogy to the example of FIG. 3. In doing so, these differing zoneson the profile tool 21 may comprise differing temperatures Twp1, Twp2,Twp3 as well as also differing material characteristics ae1, ae2, ae3.As illustrated in FIG. 4, each side of the EP-profile (over and under)is also capable of being differently shock-cooled with the correspondingprofile tool parts 21 o and 21 u. The desired extent of shock coolingfor each zone on the tool 21 is capable of being achieved by thermalconditioning (heating, cooling) and the tool temperature Twp as well asby the material characteristics ae, i.e., metallic materials andpossibly local insulating coatings.

It is instructive to discuss exemplary materials for use with the methodaccording to the invention. The LFT-mass 6 preferably comprises anaverage fiber length of at least 3 mm. Even better mechanical propertiesare achieved with greater fiber lengths of, e.g., 5-15 mm. Thecontinuous fiber reinforcement (CF) may consist of glass-, carbon- oraramide fibers, and for the highest compressive strength boron or steelfibers may be employed.

The CF-profiles may mainly be built-up of UD (unidirectional)-layers(0°) or continuous fiber strands of different kinds. It is also possibleto use layers with differing fiber orientations, for example alternatinglayers of 0°/90° or 0°/+45°/−45° fiber orientations. The CF-profiles mayalso comprise a thin surface layer (e.g., 0.1-0.2 mm) made of purethermoplastic material without any CF-fiber reinforcement.

The shock-cooling method according to the invention is particularlysuitable for crystalline materials, because it is possible to exploitcrystallisation characteristics of the materials. Especially suitablefor structural components are crystalline, or more particularlypartially crystalline polymers as the matrix of the CF-profiles 10 andof the LF-mass 6, because such polymers are capable of achieving highercompressive strengths. It is also possible, however, to utiliseamorphous polymers such as ABS or PC. The crystalline thermoplasticmaterial may, for example, consist of polypropylene (PP),polyethylene-therephthalate (PET), polybutylene-therephthalate (PBT) orpolyamide (PA). In the discussion that follows, the crystalline behaviorand the shock-cooling are further explained on the assumption thatpolypropylene PP is employed.

To this end, FIG. 5 a shows the enthalpy of polypropylene (PP) as afunction En(T) of the temperature. Curve a shows the enthalpy of the PPduring melting or heating-up. During melting, the temperature starts ata value that is lower than the melting point Tm (approximately 165° C.).As may be seen from curve a, the enthalpy increases strongly as thetemperature rises and moves toward the melting point Tm (or stateddifferently the slope of curve a is relatively high). The great increasein enthalpy (that is, the high slope of the curve) as a result of themelting of the crystalline zones. Stated differently, it takes quite abit of added heat to melt the crystalline zones of the material. If weassume that the next temperature change is a slow cooling-down, then thematerial follows curve b, in which the polymer remains amorphouslymolten down to a lower solidification temperature Tu of approx. 125° C.Only as the temperature continues to decline below Tu does enthalpystrongly decline. This range of temperatures is called the range ofcrystal growth DTkr. In the case of PP this range is approximately70-125° C., and the amount of crystal growth is shown by the curve kr).Between curves a and b in the figure is a hysteresis area DEn, whichcorresponds to the latent heat of the crystallisation.

Importantly, it can be appreciated from FIG. 5 a what happens if acooling-down is forced upon the PP so quickly that crystallization isunable to occur. The straight line c shows the path, downwards and tothe left, corresponding to a shock-like rapid cooling-down. When thishappens the polymer, which was amorphous above the temperature Tu,remains amorphous also below the temperature Tu, yet it changes itsstate from liquid to solid. Such an amorphous solid can be heated upagain in a way which follows the straight line c upwards and to theright. If we compare the amount of heat that needs to be added to bringabout a particular temperature change (for example from below Tu toabove Tm) for this amorphous material as compared with crystallinematerial, it can be seen that less heat is needed to bring about thistemperature change if the starting material is the amorphous material.The reason for this is of course that the amorphous material containsthe latent energy Den. This permits a very rapid heating-upcorresponding to the straight line c.

In the method according to the invention can be carried out by means ofthe following process steps S1-S4:

S1—Shock-cooling (ts)

S2—Transfer into the LFT-press (tt)

S3—Initial heating-up again of the profile surface layer (11) during theLFT-pressing and

S4—subsequent cooling-down during the LFT-pressing (S4.1) and after thepressing (S4.2).

These process steps are further explained in conjunction with the FIGS.5 b, 5 c, 6 and 7. FIGS. 5 b and 5 c illustrate the temperature controlon the surface 11 and in lower a layer 13 below surface 11. FIGS. 6 and7 illustrate the temperature dependence T(d) in the CF-profile 10,particularly in the CF-profile and in the LFT-mass 6 during pressing.

FIG. 5 b illustrates a temperature control on the surface 11, and inparticular in a surface layer Ta(11) during the shock-cooling in theenthalpy diagram, this in conjunction with FIGS. 6 and 7. During theshock-cooling the surface 11 of the profile within the shock-coolingperiod ts is very rapidly lowered down to the temperature Ta1 (step S1).Subsequently, during the transfer time tt a temperature equalisationwith a rapid rise again of the surface temperature to a temperature Ta2takes place (step S2), which is situated clearly below the melting pointTm. During the subsequent pressing with the liquid LFT-mass 6, theprofile surface 11 is initially heated-up again to a temperature Ta3(step S3), which is situated above the melting point Tm, and in doing sois completely melted together with the LFT-mass. Subsequently in thestep S4 a slow cooling-down takes place, initially still during thepressing (S4.1) and thereafter following the removal from the LFT-press(S4.2), wherein a further crystallisation takes place in the temperaturerange DTkr. A sufficiently good interface bonding and melting togetherCF-LFT, however, is capable of being achieved also with a strongershock-cooling with a lower surface temperature Ta3* (after step S3),which is situated clearly above Tu, but slightly below Tm.

FIG. 5 c illustrates the temperature control, and in particular thetemperature curve T(13) in a lower layer 13 below the surface 11 of theCF-profiles (e.g., at a depth of 0.1-0.4 mm), in which a highcrystallisation is produced by slow temperature control in thecrystallisation temperature range DTkr for an enhanced form stability.During the shock-cooling (S1) a strong crystallisation takes place inthe lower layer 13. During the temperature equalisation (step S2) in thetransfer time tt and initially also during the pressing (S3), aheating-up takes place, wherein the temperature, however, is kept belowthe melting temperature Tm, in order that the crystallisation remainspreserved. These temperature changes in the layer lower 13 take placemore slowly than on the surface (FIG. 5 b).

During the cooling-down (S4) a further crystallisation takes place. Thetransfer, positioning and pressing are carried out in such a way as togive rise to a stronger or weaker formation of this crystallised zone inthe layer lower 13, thereby providing a desired degree of dimensionalstability.

FIG. 6 illustrates the temperature gradient T1(d) with a surfacetemperature Ta1 in the CF-profile 10 following the shock-cooling at thepoint in time t=ts (step S1). Following the transfer into the LFT-press(step S2), rapidly a balanced temperature distribution T2(d) with areached surface temperature Ta2 is achieved after a transfer time t=tt.The crystallisation temperature range DTkr (approx. 70-125° C.), inwhich the crystal growth takes place (kr in FIG. 5 a), is alsoindicated.

FIG. 7 illustrates the temperature gradient in the CF-profile 10 and inthe adjacent LFT-layer 6 (with a thickness df) during the pressingoperation in the LFT-press. With the pressing, first the quantity ofheat Q2 is transferred from the hot LFT-layer 6 with a temperature Tf tothe CF-profile 10 (step S3). In doing so, a temperature distributionT3(d) is produced, wherein the temperature Ta3 on the profile surface 11and at the interface 9 rapidly increases strongly and with this ahigh-quality melting together is achieved, together with a high bondingstrength. Subsequently the temperature T4(d) in step S4 drops once againin correspondence with the LFT-tool temperature Twl. During the pressingtogether of CF-profiles 10 with the LFT-mass 6 and the subsequentcooling-down initially in the LFT-tool (S4.1) and then following theremoval (S4.2), the temperature control can be selected in such a mannerthat the crystalline proportion (at the required position) is increasedby means of a correspondingly slower transition through the crystalgrowth temperature range DTkr.

In analogy to the differing thermal conditioning by zone in the profiletool 21, the LFT-tool 31 may also comprise differing thermalconditionings, that is to say differing heat transfers by zone, by meansof differing parameters: tool temperatures Twl and heat penetrationcoefficients ae in different zones of the LFT-tool.

Following the removal from the LFT-tool and after the cooling-down ofthe structural components, it is possible that slight shape changesoccur, as a result of differing expansion coefficients of CF-profilesand LFT-mass and also of material contraction. These shape changes canbe influenced and indeed can be compensated for, by means of a differenttemperature control during cooling-down in some places, by analogousthermal secondary treatment, or also by a corresponding shaping of thetools, which compensates the shape change (typically by pre-forming inthe opposite direction).

In the case of partially crystalline polymers such as PP it is possibleto select the temperature control in such a manner that thecrystallisation characteristics are exploited for the improvement ofnon-deformability and bonding strength. For example:

in casing layer 12, and in particular in the layer lower 13, it ispossible to increase the strength of the casing zone in thecrystallisation temperature range DTkr;

on the profile surface 11 a minimum crystal growth can be achieved, ifthe surface temperature Ta in step S1 and step S2 is very rapidlybrought through the crystal growth temperature range DTkr and theprofile surface during the pressing is rapidly and as completely aspossible melted open and bonded with the LFT-mass (by Q2);

the shape stability is increased by a greater crystalline proportion inthe casing layer, particularly in the lower layer 13; and

depending on the required further shapability during the LFT-pressing, asmaller or greater crystalline proportion is produced in the casinglayer, particularly in the lower layer 13.

A temperature gradient at the interface 9 at the contact surface CF-LFTis capable of further increasing the strength of the joint CF-LFT bymeans of a directed crystal growth over the interface.

FIGS. 8 a, 8 b, 8 c illustrate possible shapings of the CF-profiles incorrespondence with the differing functions and requirements atdifferent points of a certain CF-profile, for example for use in astructural component so as to absorb external loads. For this purpose,the CF-profiles may comprise a three-dimensional profile shaping, whichis integrated into the structural component in a precisely definedposition. They may comprise bends, twists or folds in longitudinaldirection and they may comprise special shapings 22 for force transfersto the LFT-mass and for the direct absorption of external loads,particularly for the receiving of inserts 4 (mounting parts), at whichexternal loads are introduced into the component. The shaping of thesurrounding LFT-mass 6 is also selected to match the shaping of theCF-profiles 10. Shapings of force transfer points (of forces andmoments) inside a component (e.g., of a CF-profile through the LFT-masson to other CF-profiles) are able to be formed both as shapings 22 ofthe CF-profiles as well as shapings 32 of the LFT-mass.

To maximize strength and rigidity, it is desirable to avoid abrupttransitions between the CF-profiles and the LFT-mass and instead toemploy continuous transitions therebetween.

The three-dimensional shaping of the CF-profiles is implemented, forexample, by a pre-forming of the molten CF-tapes 5 in the horizontalplane by the tape gripper 18 and by pre-forming elements 19 during thetransfer into the CF-profile forming station 20 (refer to FIG. 11). Indoing so, the CF-tapes 5 may also be twisted. Subsequently the shapingalso takes place in the third dimension (vertically) by the profile tool21, so that to a great extent any required three-dimensionally shapedCF-profiles can be produced.

FIGS. 8 a, b illustrate the example of a complex structural component inthe form of a ⅔ rear seat back 74 with a central seat belt connection 60for the middle seat of a vehicle with several demanding loadintroductions for different load cases (crash loads). FIG. 8 a in planprojection illustrates the arrangement of the CF-profiles in thecomponent and FIG. 8 b in a perspective view the LFT-mass 6 and drawn init the integrated CF-profiles 10.1 to 10.4. This example illustrates theload-optimised shaping of the CF-profiles themselves as well as theload-optimised arrangement in a precisely defined position in thecomponent to form a structure with a corresponding shaping of theLFT-mass 6 and with an optimum bonding strength between the CF-profilescarrying the main loads (with directed continuous fibers) and thecomplementing LFT-mass (with undirected long fibers).

Here four main load carrying points L1 to L4 result from:

the loads L1, L2 on the axle holders 59 a, 59 b, around which the rearseat back is able to be swivelled,

the load L3 on the lock 58, for fixing the rear seat back in its normalposition and

the load L4 on the belt lock, resp., belt roller 60 for the central beltof the middle seat.

With this structural component the following load cases (with thefurther loads L5 to L9) are covered:

Front- and Rear Collision

Securing of Any Goods Loaded

Belt Anchoring

Head support anchoring.

For the receiving and transferring of all loads and forces theintersecting CF-profiles together with the joining force-transmittingshapings of the LFT-mass form a spatial, three-dimensional intersectionstructure 50. Here the CF-profiles respectively in pairs in theLFT-shapings form a moment-transmitting girder subject to bending:

The CF-profiles 10.1 and 10.4 in a crimp 7 of the LFT-mass form a girdersubject to bending between the loads L1 and L4

and the CF-profiles 10.2 and 10.3 in the ribs 8 of the LFT-mass a girdersubject to bending between the loads L2 and L3.

Through the three-dimensional intersection point 50, in this the load L4on the belt roller and also in part other loads, which act on the girdersubject to bending 10.1/10.4, is also supported on the other girdersubject to bending 10.2/10.3 (and vice-versa).

The main forces, resp., loads L1 to L4 are received by means of forceintroduction points:

through shapings 22 and 32 of the CF-profile ends and of the LFT-massfor receiving the external forces with or without inserts 4.

In doing so, the inserts 4 prior to the pressing operation are able tobe inserted into the LFT-tool and then pressed together with theCF-profiles and the LFT mass

or else it is also possible to fit them into the component later on.

Here the CF-profile 10.1 comprises an arc-shaped widening 22.1 forreceiving an insert 4 at the axle bearing 59 a. The other axle holderreceptacle 59 b is formed by shapings 22.2 of the CF-profiles 10.2 and10.3 and by adapted joining shapings 32.2 of the LFT-mass. These profileends 22.2 are bent over and in this manner anchored in the LFT-mass forthe purpose of increasing the tensile strength. The lock 58 is bolted onto a lock plate on the CF-profile 10.3 and supported by the CF-profile10.2. The belt roller 60 is supported by shapings 22 of the CF-profiles10.1 and 10.4 and by LFT-shapings 32.

The smaller loads L8, L9 of head supports 61 here are absorbed throughLFT-shapings 32. For reinforcement, however, it would also be possibleto integrate an additional CF-profile 10.5 deposited transversely (insome zones oriented flat or vertically).

In this example the three-dimensional profile shaping is evident in manyvariants.

The depositing sequence of the CF-profiles into the LFT-tool is:

first the CF-profile 10.1, thereupon the CF-profiles 10.2 and 10.3 andsubsequently the CF-profile 10.4. Then the liquid LFT-mass 6 isintroduced and the complete component pressed in a single step as asingle piece and as a single shell. In order to obtain as short aspossible transfer times tt, several or all CF-profiles (10.1-10.4) areable to be gripped with a multiple gripper 26 or robot, pre-positionedcorrectly relative to one another during the transfer and be insertedinto the LFT-tool 31 together in a single step.

During the form pressing of the CF-profiles it is also possible to pressseveral profiles in one profile tool 21 with a profile forming station,e.g., here the CF-profiles 10.2 and 10.3.

The profile shaping in the CF-profile forming station 20 in case ofparticularly complicated shapes may also be carried out by means of amultipart profile tool in a multi-stage shaping process. An example forthis is illustrated in FIG. 8 c with a three-part tool 21 u, 21 o and21.3. In a two-stage shaping process, here first the tool parts 21 o and21 u are closed and thereupon immediately on the side the tool part21.3. In this manner it is possible to shape a 90° or 180°-arc—e.g., forzones, where forces are to be introduced.

FIGS. 9 a, 9 b illustrate an example of a CF-profile 10, which over itslength comprises differing cross-sectional shapes, this in adaptation tothe forces to be transmitted and for the optimum bonding with theLFT-mass 6. The Figures in cross-sectional view illustrate a CF-profile10 a, 10 b in a rib 8, e.g., corresponding to the profiles 10.2 or 10.3of FIG. 8, at two different locations.

FIG. 9 a illustrates a shaping 10 a with a positioning shoulder 55 forfixing and holding the CF-profile in the required position—thisespecially during pressing, when the liquid LFT-mass is pressed into therib. On top and underneath the CF-profile respectively comprises athicker zone 56 as tensile—and compressive zones (in longitudinal fiberdirection) for the transmission of moments. Located in between is athinner thrust zone 57 with a correspondingly thicker adjacent LFT-layer6 and with a large bonding surface area and a particularly stronginterface joint.

With this, the shear resistance is increased by the adjacent LFT-layer 6with isotropic fiber distribution (while the strength transverse to thefiber orientation in the CF-profiles 10 here is lower).

At another location according to FIG. 9 b the profile cross-section 10 bis changed corresponding to the force situation there: stretched, i.e.,higher and narrower and without a positioning shoulder.

For the secure and accurate positioning and fixing of the CF-profiles,during the pressing with the LFT-mass, further positioning points 54 maybe developed on the CF-profiles, which correspond to the shaping of theLFT-tool 31 o (top) and 31 u (bottom). Here the positioning point 54serves for the accurate positioning below in the rib 8. Positioningpoints can also be arranged suitably distributed in the longitudinaldirection of the CF-profiles.

In an analogous manner, profile shapes of this kind may also bepositioned and fixed on crimped walls instead of in ribs 8.

Instead of the examples 8 a, 9 a, it is also possible to design thecross-sections of CF-profiles as “L”- or “Z”-shaped, depending on theapplication.

In addition to the shock-cooled CF-profiles, further shaped CF-profiles,which, however, have been treated separately and in a thermally inversemanner (i.e., solid inside, liquid outside), may be brought into theLFT-tool for the non-deformable transfer and pressed together with theshock-cooled CF-profiles in a single step. As an example, the CF-profile10* according to FIG. 10 as a result of external heating-up is capableof comprising a molten external zone 89 and a still non-deformablecooler internal zone 88. For the handling and transfer, this CF-profile10* may be gripped by means of cold grippers at non-sticking contactpoints (which are thereby cooled) for a short period.

FIGS. 11 and 12 illustrate examples of a CF-profile production line, andin particular of an installation for the implementation of the methodaccording to the invention. FIG. 11 depicts an example of a CF-profileproduction line with a CF-profile forming station 20, with asemi-finished products store 14, a heating station 15, with a protectiongas atmosphere 27 (e.g., with N2, for critical materials andtemperatures), with a conveyor belt or a chain conveyor 16 (e.g., astudded chain with a non-sticking coating and a brush cleaning system),a band gripper 18 with pre-forming elements 19, which are attached tothe upper CF-profile tool 21 o, a CF-profile forming station 20 withshock-cooling, with a transfer portal 17 for the upper tool part 210 andwith a CF-profile press 23. With a profile gripper 26 and a transferrobot, particularly a handling unit 42, the produced CF-profiles aretransferred into the tool 31 of an LFT-press 30 and accuratelypositioned. From the semi-finished products store 14, the CF-tapes 5having been cut to a suitable size (also with varying length, width andthickness) are brought to the heating station 15 with the chain conveyor16 and there, e.g., with IR-radiators are completely melted open andheated-up to a homogeneous required tape temperature Tp0. Subsequentlythe molten CF-tapes 5 are gripped with a band gripper 18 withpre-forming elements 19, which are attached to the upper tool part 21 o,and during the transfer into the CF-profile forming station 20 arepre-formed (pre-formed in the horizontal plane, e.g., by means ofpositioning pins with bending or rotation of the molten tape), movedover the lower profile forming tool 21 u with the transfer portal 17,deposited there in the required pre-formed position and immediatelypressed in the precisely defined, adjustable shock-cooling period ts forthe formation of the dimensionally stable casing layer 12. By means ofthe deformation in the profile tool, the required, definedthree-dimensional shape of the CF-profile is obtained. Subsequently theCF-profiles 10 are immediately removed from the mould and with theprofile gripper 26 transferred into the LFT-tool 31 of the LFT-press 30by the robot 42 and accurately positioned. With the profile gripper 26the CF-profiles 10 during the transfer are aligned to the requiredset-point position in the air, i.e., with respect to translation motion,rotation and inclination into the defined position for each individualCF-profile. With a profile gripper 26, such as a robot, the profiles areable to be individually gripped and transferred or else also severalprofiles gripped at the same time and simultaneously respectivelyaligned to the correct position and then deposited together.

In the example of FIG. 8, first the profile 10.1 is positioned, andthereupon together the CF-profiles 10.2 and 10.3 are each respectivelyvertically positioned in a rib and then the CF-profile 10.4 ispositioned in a crimp, wherein also these four profiles are capable ofbeing simultaneously transferred and positioned with a multiple profilegripper 26.

In order to avoid the molten CF-tapes 5 remaining stuck to the bandgripper 18 and to the pre-forming elements 19, the tapes are able to beunstuck by means of a brief contact with cold gripper surfaces, which donot stick. A double-gripper of this type 18 a, 18 b comprises, e.g., twoinsulating small gripper contacts 18 a and two stronger, cold,non-sticking gripper contacts 18 b.

In a CF-profile forming station 20, with more than one profile tool21.1, 21.2 it is also possible to simultaneously press severalCF-profiles 10.

FIG. 12 illustrates a complete installation 40 with several CF-profileproduction lines with CF-profile forming stations 20.1, 20.2, 20.3 aswell as with an LFT-processing facility 34, e.g., an extruder, and withan LFT-gripper 37 for transferring the molten LFT-mass 6 with therequired temperature into the LFT-press 30, for example into theLFT-tool 31. The installation comprises partial control systems for theindividual sub-assembly groups: a control 25 of the CF-profile formingstations, a control 35 of the LFT-processing facility and an LFT-presscontrol 36, which can be combined in the installation control system 45including the control system for the transfer robot 42.

FIG. 13 illustrates the accurately defined positioning of severalCF-profiles (10.1-10.4) in an LFT-tool in differing fitting positionsand with any needed inclinations between flat and vertical. In this, theindividual CF-profiles can be positioned on the lower tool 31 u and/oralso on the upper tool 31 o and also be fixed with suitable fixingelements 38. With the LFT-mass 6 introduced in between thereforecorrespondingly also components with elaborate CF-profile reinforcementstructures can be produced in a single step.

The LFT-mass 6 may also be introduced and pressed with other analogouscompressive manufacturing processes instead of extruding. Thus it isalso possible to utilise LFT-injection processes with horizontalpressing and a vertical LFT-tool. Applicable as particularly suitable isalso an injection moulding process with back pressing in the source flowwith a moving tool with submerged edges, where the tool during theinjection is first slowly opened and then pressed together. It is alsopossible, however, to implement a horizontal pressing with a verticalLFT-tool. Vertical injection with a horizontal LFT-tool is alsopossible.

Structural components according to the invention contain one or moreshock-cooled CF-profiles 10, which comprise a precisely defined shapingand a precisely defined position in the LFT-mass 6 and therefore also inthe structural component, so that external loads to be carried arecapable of being optimally carried and supported. The productionaccording to the invention in the shock-cooling process is able to beproven on finished structural components, e.g., by distinguishingshaping marks on the CF-profiles, which have been created by thehandling elements during the production process, by slight roundings ofedges on the CF-profiles and by harmoniously balanced transitionsbetween CF-profiles and LFT-mass.

In the case of the preferred crystalline thermoplastic materials, on theCF-profiles 10 in preference in the zone of a lower layer 13 (of, e.g.,0.2-0.4 mm thickness) below the profile surface 11 an increasedcrystallisation 101 is generated (refer to FIG. 7).

On the contact surfaces 9 between CF-profiles 10 and LFT-mass 6, inpreference a directed crystallisation 102 over the contact surface isgenerated. This also results in improved mechanical properties and in animproved stability over time of the structural components withshock-cooled CF-profiles.

Light, load-bearing structural components according to the inventionwith integrated, shock-cooled CF-profiles are capable of being employedin a broad range of applications, e.g., in vehicle construction forcomponents such as chassis parts, doors, seating structures, tailgates,etc. The structural components in some applications can also beconstructed with solely one integrated, suitable shaped CF-profile. Twoexamples of structural components with one single CF-profile areillustrated in FIGS. 14 and 15.

FIG. 14 illustrates a bumper beam support 92 with a CF-profile 10.1integrated into the forming LFT-mass 6, which extends over the wholelength. At two load receiving points L1, the bumper beam support 92 isconnected with the vehicle chassis. The CF-profile 10.1 here is designedas “top-shaped”, with slanting flanks 93 and integrated into theLFT-mass, as a result of which also an energy-absorbing crash-element iscreated. In another, reinforced variant, alternatively it would also bepossible to integrate a second CF-profile 10.2 on a crimp underneath theCF-profile 10.1.

FIG. 15 illustrates an assembly support (front end) 95 with anintegrated CF-profile 10.1 bent on both sides with four load receivingpoints L1, L2, where the assembly support is attached to the chassis.Depending on requirements, the CF-profile 10.1 may also comprise ashaping or recess at these points L1, L2, which, integrated into theLFT-mass as a crash-element 93 is plastically deformable—in analogy tothe example of FIG. 14.

Within the scope of this description, the following designations areused:

-   -   1—Structural component    -   1.2—Second part (two-shell)    -   4—Inserts, inlays    -   5—CF-tapes, CF-bands    -   6—LFT-mass, form mass    -   7—Crimp    -   8R—ib    -   9—Interface, contact surface CF-LFT    -   10 CF-profiles    -   11—Profile surface    -   12—Casing layer    -   13—Lower layer (layer below 11)    -   14—Semi-finished products store    -   15—Heating station    -   16—Chain conveyor    -   17—Transfer portal    -   18—Band gripper    -   19—Pre-forming elements    -   20—CF-profile forming station (shock cooling)    -   21—Profile tool    -   21 o, 21 u—Upper, lower    -   22—CF-profile shapings    -   23—Profile press    -   25—Control of CF-profile forming station    -   26—Profile gripper    -   27—Protection gas atmosphere    -   30—LFT-press    -   31—LFT-tool    -   31 o, 31 u—Upper, lower    -   32—LFT-shapings    -   34—LFT-processing, extruder    -   35—LFT-control of 34    -   36—LFT-press control    -   37—LFT-gripper    -   38—Fixing elements    -   40—Installation    -   42—Transfer robot, handling unit    -   45—Installation control system    -   50—Three-dimensional intersection point    -   54—Positioning points    -   55—Positioning shoulder    -   56—Thick tensile—and compressive force zones in 10    -   57—Thinner thrust zone    -   58—Lock    -   59 a,b—Axle holders    -   60—Belt roller, belt connection, belt lock    -   61—Head supports    -   88—Internal zone    -   89—External zone    -   92—Bumper beam support    -   93—Crash element    -   95—Assembly support, front end    -   101—Enhanced crystallisation    -   102—Directed crystallisation    -   LFT—Long fiber thermoplastic    -   CF—Continuous fiber    -   ae—Heat penetration coefficient    -   d—Direction vertical to the profile surface 11    -   dp—Thickness of the profile    -   df—Thickness of the LFT-layer    -   Q1—Heat transfer at 21    -   Q2—Heat transfer from 6    -   t—Times, periods    -   ts—Shock-cooling period    -   tt—Transfer time    -   T—Temperatures    -   Ta—Surface temperature    -   Ti—Temperature inside, internal temperature    -   Twp-T of CF-profile tool 21    -   Twl-T of LFT-tool 31    -   Tf-T of LFT-mass    -   Tm—Melting temperature    -   Tp0-T of CF-tape 5    -   Tp—Input temperature of CF-profile 10    -   Tu—Lower solidification temperature    -   T1, T2—Profile temperature curves    -   DTkr—Crystallisation temperature range    -   kr—Crystal growth    -   DEn—Hysteresis range (crystallisation heat, latent enthalpy)    -   L—Loads    -   En—Enthalpy    -   S1, S2, S3, S4—Process steps

1. A structural component with partially crystalline thermoplasticmaterial and with at least one CF-profile integrated in an LFT-mass,which is produced in a single stage LFT-pressing manufacturing process,the method comprising the steps of: melting impregnated CF-tapes in aheating station; subsequently transferring the melted CF-tapes into atwo-part profile tool of a CF-profile forming station; within theCF-profile forming station, pressing the CF-tapes for a time period bymeans of heat transfer to the thermally conditioned profile tool, toyield a shock-cooled, solidified, dimentionally stable casing layer, aninner part of the CF-tapes remaining melted, and the CF-tapes defining aCF-profile; after the pressing and shock cooling, separating theCF-profile from the profile tool; after the separating, transferring theCF-profile into an LFT-tool and positioning the CF-profile in a definedmanner; after the positioning, introducing a molten LFT-mass into theLFT-tool; pressing the LFT-mass together with the CF-profile; so thatduring the pressing of the LFT-mass together with the CF-profile, thecasing layer is melted again at the surface and is thermoplasticallymelted together with the surrounding LFT-mass and wherein theCF-profiles in a zone of a lower layer below the profile surfacecomprise an increased proportion of crystalline material.
 2. Thestructural component of claim 1 wherein, at contact surfaces betweenCF-profiles and LFT-mass it comprises a crystallisation with a directedcrystal growth through over the contact surface.
 3. A method for theproduction of structural components out of long-fiber thermoplastic(LFT) with integrated continuous-fiber (CF) reinforcements in a singlestage LFT-pressing manufacturing process, the method comprising thesteps of: melting impregnated CF-tapes in a heating station;subsequently transferring the melted CF-tapes into a two-part profiletool of a CF-profile forming station; within the CF-profile formingstation, pressing the CF tapes for a time period by means of a heattransfer to the thermally conditioned profile tool, to yield ashock-cooled, solidified, dimensionally stable casing layer, an innerpart of the CF tapes remaining melted, and the CF tapes defining aCF-profile; after the pressing and shock cooling, separating theCF-profile from the profile tool; after the separating, transferring theCF-profile into an LFT-tool and positioning the CF-profile in a definedmanner; after the positioning, introducing a molten LFT-mass into theLFT-tool; pressing the LFT-mass together with the CF-profile; so thatduring the pressing of the LFT-mass together with the CF-profile, thecasing layer is melted again at the surface and is thermoplasticallymelted together with the surrounding LFT-mass.
 4. The method of claim 3wherein as the LFT-pressing manufacturing process, an LFT-extrusionprocess with a vertical LFT-press and a horizontal pressing tool isutilised.
 5. The method of claim 3 wherein the LFT-pressingmanufacturing process comprises an LFT-injection moulding process. 6.The method of claim 5 wherein the LFT-injection moulding processcomprises a back pressing in the source flow.
 7. The method of claim 3wherein several CF-profiles are positioned in the LFT-tool andsubsequently pressed together with the LFT-mass.
 8. The method of claim3 wherein CF-profiles are simultaneously produced in more than oneCF-profile production line.
 9. The method of claim 3 wherein in theprofile tool, more than one CF-profile is produced.
 10. The method ofclaim 3 wherein the CF-profile forming station comprises more than oneprofile tool, so that a plurality of CF-profiles are pressedsimultaneously.
 11. The method of claim 3 wherein in the CF-profileforming station, a multi-stage profile forming process is carried out bymeans of a multi-part profile tool.
 12. The method of claim 3 whereinthe melted CF-tapes are pre-formed in plastic condition by pre-formingelements during the transfer into the profile tool.
 13. The method ofclaim 3 wherein the shaping of the CF-profile comprises athree-dimensional profile shaping.
 14. The method of claim 3 wherein theCF-profile in longitudinal direction comprises a bend, a twist, a fold,or a surface structuring and wherein the CF-profile has differingcross-sectional shapes.
 15. The method of claim 3 wherein theshock-cooling period has a duration in the range of from 1 to 5 sec. 16.The method of claim 3 wherein the LFT-mass comprises an average fiberlength of at least 3 mm.
 17. The method of claim 3 wherein thethermoplastic material consists of partially crystalline polymers. 18.The method of claim 3 wherein the thermoplastic material consists ofpolypropylene, polyethylene-therephthalate, polybutylene-therephthalateor polyamide, and the continuous fiber reinforcement consists of glass-,carbon- or aramide-fibers.
 19. The method of claim 3 wherein theCF-profiles comprise a surface layer of 0.1 to 0.2 mm of purethermoplastic material without CF-fiber reinforcement.
 20. The method ofclaim 3 wherein the CF-profiles are built-up out of layers withdiffering fiber orientations.
 21. The method of claim 3 wherein theCF-profiles comprise locally differing shock-cooling zones.
 22. Themethod of claim 3 wherein a surface of the CF-profile adjacent to theLFT-tool has been shock-cooled to a larger extent on one side than onthe opposite side.
 23. The method of claim 17, wherein the surfaces ofthe CF-profiles following the shock-cooling are very rapidly broughtback again to a temperature above DTkr from a temperature below thecrystallisation temperature range DTkr.
 24. The method of claim 17wherein during the shock-cooling with a slower passage through acrystallisation temperature range DTkr, a corresponding crystallineproportion is generated in a lower layer.
 25. The method of claim 3wherein the CF-profiles are positioned in shapings of the LFT-tool indiffering fitting positions.
 26. The method of claim 3 wherein anIR-heating station with a protection gas atmosphere, a chain conveyor, atransfer robot with grippers for transferring of the CF-profiles andmolten LFT-mass, an LFT-extruder, an LFT-press and an installationcontrol system with partial controls for the different stations.